1. Field of the Invention
The present invention relates to a swinging and tilting mechanism, a lens barrel, and an image capture apparatus making up an optical system enabling so-called swinging and tilting photographing based on the Scheimpflug principle.
2. Description of the Related Art
In related art, a lens barrel enabling swinging and tilting photographing by displacing an optical axis of a photographing optical system from a center of a film or an imager device has been provided. This type of lens barrel includes a bellows that connects a support plate attached to a lens mount and a support plate provided on a body mount side, using a bellows attachment, and a support mechanism that slidably supports both the support plates to slide the lens barrel. Moreover, there is also proposed a swinging and tilting lens barrel using a cam mechanism that is more simplified in configuration than the lens barrel using the bellows attachment, and is easy to handle and carry (see Japanese Patent Application Laid-Open No. 2000-66263 (Patent Document 1)).
The lens barrel described in Patent Document 1 includes a lens holding frame that holds a lens, a reference cylinder in which rectilinear grooves through which a plurality of guide pins projected from the lens holding frame are inserted are extended in an optical axis direction, and a cam cylinder that is externally fitted onto the reference cylinder so as to be circumferentially rotatable, and is formed with cam grooves with which the respective guide pins inserted through the rectilinear grooves are engaged. The cam grooves formed in the cam cylinder include linear groove portions that is formed along a circumferential direction about an optical axis, and inclination groove portions that incline in the optical axis direction with respect to the linear groove portions, along a circumferential direction of the cam cylinder.
In the above-described lens barrel, the rotation of the cam cylinder allows the guide pins to be moved in accordance with the cam groove shape and tilted along the rectilinear grooves provided in the reference cylinder. Thereby, the lens held by the lens holding frame is tilted with respect to the direction where the rectilinear grooves are formed, so that tilting or swinging operation is performed.